tlb parent
The whole thing is a test. The risk of huge explosions starts when they load it with fuel, not when they fire the engines. There are risks even before that, like electrical fires or structural failures.
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It's easy to make structures that don't fail: just make them 5x stronger than anticipated max loads.
Sadly, this would make a rocket too heavy to reach orbit. So they end up being 1.1x stronger than anticipated loads. And it's hard to exactly anticipate loads. Vibration can add to a peak load, and it's notoriously hard to model how much vibration might happen. SpaceX rockets are filled with cryogenic methane at -160C, which causes everything it touches to shrink which creates forces between the parts that get cold and the parts that don't. A rocket-sized tank contracts by inches, but has to be supported by the structure around it. A single support member that doesn't move the right way can cause a fracture. So it's actually a hard problem.
There are is a way[1] how to gate a spacecraft 5x stronger (basically on the level of battleship style steel plate) to orbit - and then to Titan and back. The propulsion method just has some unfortunate side effect when launching from earths surface. Still it should work just fine & might come in as a handy option handy in an emergency.
[1] https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...